Engine to shaft coupling, different sizes

[GILow]

Hi all,

My new engine has a smaller diameter on the output flange than the original engine.

The current Polyflex coupling is very old, so I was intending to replace it anyway.

Polyflex can make a custom adapter to attach to the new coupling to match the sizes, it I thought I should see if there are any products that people know of that address this particular issue.

Current shaft flange has a 4.25 inch bolt circle diameter, the new engine has a an 82.5 mm bolt circle diameter.

I have HEAPS of room thanks to the much smaller engine, so the adapter can be as thick as needed (within reason).

Any recommendations?

[JPA Cate]

If they can make the custom adapter for you, go for it! Make the installation as simple as possible and finish it up and tell us all how it went! No over-thinking!

Ann

[GILow]

Originally Posted by JPA Cate

If they can make the custom adapter for you, go for it! Make the installation as simple as possible and finish it up and tell us all how it went! No over-thinking!



Ann

Overthinking...? Me?

Let me think about that and I’ll get back to you.

But, Beta Marine Australia are very happy about the Polyflex couplings and recommend them and one other sort to clients.

[sailormed]

If you have the money to spend on a Sigma drive the this is the moment. They will compensate for +- 3° and transmit thrust.

[Fore and Aft]

GiLow Polyflex is the best. You can go to their workshop in Redcliffe and actually speak to the guys making the mounts and adapter. They are so good a few years ago I was passing through Redcliffe very early in the morning and although the office was closed the workshop had my mounts waiting for me.
Cheers

[GILow]

Originally Posted by sailormed

If you have the money to spend on a Sigma drive the this is the moment. They will compensate for +- 3° and transmit thrust.

That’s a good point. I did seriously consider it, and it would be easy to fit, but in the end I felt that the install and alignment are so simple in my boat that adding such a drive would be adding potential problems rather than solving them. (Though I believe they are very reliable.)

[GILow]

Originally Posted by Fore and Aft

GiLow Polyflex is the best. You can go to their workshop in Redcliffe and actually speak to the guys making the mounts and adapter. They are so good a few years ago I was passing through Redcliffe very early in the morning and although the office was closed the workshop had my mounts waiting for me.

Cheers

That’s good to know, thank you. I have always suspected that they are good, but it’s good to hear it from a trade pro.

[Disailor]

Here's a thought: Remove the rubber from the old coupling & duplicate it from a section of old tire!

[GILow]

Originally Posted by Disailor

Here's a thought: Remove the rubber from the old coupling & duplicate it from a section of old tire!

Very... um... cost effective.

I’ve just been having a laugh with the Polyflex rep after I realised my tired old prop shaft flange was troubling his sense of the aesthetic more than any particular engineering concern.

I think I’ll forward your tyre idea to him and see how much of a reaction I can get.